Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness

Anne Marie Chang, Daniel Aeschbach, Jeanne F. Duffy, Charles A. Czeisler

Research output: Contribution to journalArticlepeer-review

437 Scopus citations

Abstract

In the past 50 y, there has been a decline in average sleep duration and quality, with adverse consequences on general health. A representative survey of 1,508 American adults recently revealed that 90% of Americans used some type of electronics at least a few nights per week within 1 h before bedtime. Mounting evidence from countries around the world shows the negative impact of such technology use on sleep. This negative impact on sleep may be due to the short-wavelength-enriched light emitted by these electronic devices, given that artificial-light exposure has been shown experimentally to produce alerting effects, suppress melatonin, and phase-shift the biological clock. A few reports have shown that these devices suppress melatonin levels, but little is known about the effects on circadian phase or the following sleep episode, exposing a substantial gap in our knowledge of how this increasingly popular technology affects sleep. Here we compare the biological effects of reading an electronic book on a light-emitting device (LE-eBook) with reading a printed book in the hours before bedtime. Participants reading an LE-eBook took longer to fall asleep and had reduced evening sleepiness, reduced melatonin secretion, later timing of their circadian clock, and reduced nextmorning alertness than when reading a printed book. These results demonstrate that evening exposure to an LE-eBook phase-delays the circadian clock, acutely suppresses melatonin, and has important implications for understanding the impact of such technologies on sleep, performance, health, and safety.

Original languageEnglish (US)
Pages (from-to)1232-1237
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume112
Issue number4
DOIs
StatePublished - Jan 27 2015

All Science Journal Classification (ASJC) codes

  • General

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